Optimization of vaccine antigen for the development of improved influenza vaccines ABSTRACT: Despite over 70 years of vaccine development, influenza remains a persistent global challenge for public health authorities. Even with high public awareness and sustained vaccination efforts by health agencies, influenza is still estimated to cause greater than 200,000 annual hospitalizations in the U.S., with more than 20,000 deaths. On a global scale, the WHO estimates that seasonal influenza is responsible for 3-5 million cases of severe disease and up to 500,000 deaths each year. While heterotypic shifts in influenza A subtypes (e.g., H1 vs H3) play a substantial role in this challenge, recent studies have shown that even homotypic protection is rapidly lost throughout each influenza season, substantially limiting vaccine efficacy. The majority of currently licensed influenza vaccines rely on inactivated viral antigens, but the method of inactivation is becoming outdated, relying on inactivation approaches that are limited to b-propiolactone, formaldehyde or ultraviolet irradiation. However, we and others have shown that optimal inactivation is crucial for maintaining key antigenic epitopes and eliciting robust protective immunity, and that many common inactivation methods fail to produce optimal vaccines. To better address this unmet need, we have developed an advanced oxidation-based approach to virus inactivation and discovered a unique technique for protecting antigenic epitopes that results in more immunogenic vaccine formulations. In particular, we have established an approach based on Fenton-type oxidation chemistry, using optimal concentrations of Cu2+ (cupric ion) in conjunction with H2O2 (hydrogen peroxide). Moreover, we have identified a novel Cu2+ carrier molecule that not only reduces antigenic damage but also provides more efficient virus inactivation. Here, we provide preliminary data on this exciting and innovative new platform technology, which demonstrates rapid virus inactivation while fully preserving viral HA (hemagglutination) activity and greatly improved in vivo potency. We propose a detailed research plan to expand on this novel approach to influenza inactivation, with the ultimate goal of developing improved vaccine formulations able to elicit durable vaccine-mediated immunity for the prevention of seasonal influenza.